Mars is the fourth planet from the sun and the second-smallest planet in the solar system. It has long been called the "Red Planet," due to the abundant iron oxide on its surface giving it a reddish appearance when seen from Earth. For much of modern history, Mars was considered the planet most likely to host extraterrestrial life because of its Earth-like size (0.107 Earths in mass, 0.151 Earths in volume) and orbit (1.5 astronomical units or 230 million kilometers from the sun, with an... więcej

Salem Press Encyclopedia of Science, 2024. 3p.